This invention relates to a hearing aid having at least one rechargeable battery, and in particular, to a recharging system that is easily configured to receive hearing aids of distinct shapes and sizes.
Hearing aids having rechargeable batteries have been known in the art for a long time; e.g., see U.S. Pat. No. 3,297,933 (McCarthy). The trade-off between rechargeable batteries and non-rechargeable batteries is the inconvenience of having to replace a battery. There is also a trade-off in capacity. A non-rechargeable battery lasts much longer than a rechargeable battery having the same outside dimensions as the non-rechargeable battery. This is due to the different chemistries of the two types of batteries.
The inconvenience of having to remove the battery from a hearing aid initially applied both to rechargeable batteries and non-rechargeable batteries. The sole advantage of rechargeable batteries was not having to be replaced. Then, chargers were developed that made electrical contact with a hearing aid, obviating the need to remove the rechargeable battery; e.g. see U.S. Pat. No. 3,493,695 (Stork). This simplified matters for those lacking the dexterity to remove and insert a battery.
A problem remains with the diversity of hearing aids on the market. The most obvious difference is between in-the-ear hearing aids and behind-the-ear hearing aids. Even within a given type, there are variations in shape and size that must be accommodated. Preferably, each hearing aid is held optimally so the user can readily insert and remove the hearing aid from the charger. The cost of manufacturing and storing the various unique chargers can add considerably to the cost of a hearing aid system, even if the charger can charge two hearing aids simultaneously.
Simply making a chamber large enough to drop in a hearing aid of almost any shape does not assure proper contact for charging. A hearing aid must be positioned correctly to assure electrical contact. Within a charger, the contact leaves or pins must be properly aligned for contact and be able to withstand repeated use.
In view of the foregoing, it is therefore an object of the invention to provide a battery charger that can be adapted to hearing aids of distinctly different shapes and sizes.
Another object of the invention is to provide a battery charger for a hearing aid that reliably connects electrically to the hearing aid.
A further object of the invention is to reduce the cost of manufacturing battery chargers for hearing aids.